Jack - Be aware, she may simply see you as a friend.
As a confirmed and long-term student of the way women think, I have learned one very important lesson - if a girl is interested in you as a boyfriend, she will let you know.
What you need to be aware of is, seeing 'signals' that are not really there, because you wish they were - such as the pressing her head against your knee.
You would love that to be a 'sign of interest' - trust me, it's not.
If you get to the stage where yuu go out for an evening, there will come the 'goodnight' part, and here again, if she wants you to kiss her, she will let you know.
She will face you, maker prolonged eye contact, maybe move towards you, and if these things don't happen, don't act as though they have because you wish they had.
Trying to kiss a girl who doesn;t feel that way is a bell you can't un-ring, and you may lose a potential friend through it.
Remember - missing the opportunity to move things forward is not a big deal - it's a forward stop you can make another time.
Taking an opportunity that is not really there is a big deal, you can't step back from that.
Take it nice and steady, don't rush, read the signs that are there, even if they are not ones you hoped for, that way you will keep your dignity!
Good luck.